Impact of "Standard" Earmold on RECD

Abstract

Output from a moderate-gain behind-the-ear hearing aid was measured in HA-1 and HA-2 couplers. For the HA-1 coupling, a standard full-shell earmold with #13 tubing throughout was used. The results suggest that when this earmold configuration is used, the gain and output assumed from HA-2 specifications may not be realized in the higher frequency region. Questionnaires sent to all U.S. earmold manufacturers indicated that only one of those manufacturers considered a “standard” earmold to be one incorporating a “horn” effect in the canal portion of the mold; over 70% of the manufacturers reported inserting tubing to the end of the canal portion as a standard procedure. Measures of real-ear-to-coupler differences (RECD) should be obtained with consideration for this earmold effect.